Telephone system



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6 Sheets-Sheet 2. A. GRAHAM. TELEPHONE SYSTEM.

No. 437,986. Patented Oct. 7, 1890.

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No. 437,986. Patented Oct. '7, 1890.

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TELEPHONE SYSTEM.

No 437,986. Patented Oct. '7, 1890.

INVENTOR [NUMA WITNESSES UNITED STATES PATENT OFFICE.

ALFRED GRAHAM, OF LONDON, ENGLAND, ASSIGNOR To THE CONSOLIDATED TELEPHONE CONSTRUCTION AND MAINTENANCE, COMPANY, LIMITED,

OF SAME PLACE.

TELEPHONE SYSTEM.

SPECIFICATION forming part of Letters Patent No. 437,986, dated October '7, 1890.

Application iled December 27, 1889. Serial No. 335,096. (No model.) Patented in Bngland'April 5, 1889, No. 5,867.

Great Britain, No. 5,867, dated April 5, 1889,).

1o of which the following is a specification.

The object of this invention is to provide a simple, convenient, and eicient switchgfor telephone-circuits by means of which `contacts can be made for communicating with -15 diierent places, and in which means are provided whereby the return of the contactmaker to its normal position is insured when the operator has iinished using the instrument, for which purpose, according to this inzo vention, the lever which supports the receiver when not in use is provided with or attached to a spring or other device, which when the receiver isV removed from the lever takes up such a position that when the receiver is 2 5 againplaced on the lever the spring operates the detent or retaining device by which the contact-maker has been held in position for use, so that the said contact-maker returns to its normal position of zero.

3o Figure l of the accompanying drawings is a front elevation of an apparatus constructed according to this invention. Fig. 2 is a transverse section taken along the line l 2 in Fig. l; and Fig. 3 is a view of the interior looking 3 5 from the back, the back board being removed.

Fig. 4 is a diagram showing the lines communicating with the several switches in the series; and Figs. 5, 6, 7, and 8 are diagrams of the circuits at different stages of the opera- 4o tion of the apparatus.

The switch shown in the drawings is arranged for communicating with nine other stations, each of which is provided with a similar switch. Each switch is provided with 45 stationary contacts formed by blade-springs d, preferably arranged in an arc of a circle on the back of the front board A, with either of which contacts d a movable contact B may be brought into contact, as required. The

5o movable contact B is mounted on the inner end of a spindle b, which passes through the front board A and has fast on its outer end a handle C, by which the Contact B may be moved, a pointer c being also fixed on the spindle for indicating on a scale on the face 55 of the board which of the contacts are made. Each switch contains one stationary contact a, indicated on the scale by 0, (zero.) The number of the station in the Series to which the switch belongs is omitted from the scale. 6o For example, as shown in Fig. 4, No. l switch contains contacts marked 0 2 3 4 5, and so on; No. 2 switch, O 1 3 4 5, and so on; No. 3 switch, 0 l 2 4 5, and so On;ANO. 4 switch, O l

2 3 5, and so on; and No. 5 switch, O l 2 3 4 65 6, and so on. The switch shown in the drawings has omitted from its scale the number 5, thus indicating that the switch belongs to No. 5 station of the series. The line-wires from the several stations in the series enter 7o the switch through a hole CZ in the back board D, and are connected to spring-contact plates e, which when the front board A is in position make contact with spring-plates f thereon, which latter plates are connected by wires 7 5 g with the stationary spring-contacts @,hereinbefore referred to.

On the spindle b,which carries the movable contact B, there is a notched wheel E or segment of a wheel having teeth with which en- 8o gages a detent h, carried by a lever F, which is centered att' to the front board A. The teeth on the wheel E are of Vsuch a shape as to admit of the wheel being turned freely in either direction by the handle C, the detent 85 in that case slipping lover the teeth.

Surrounding the spindle h is a spiral spring 7c, having one end connect-cd to the spindle and its other end attached to the lever F, so that this spring serves to hold the detent in 9o engagement with the teeth on the wheel E, and also to return the movable Contact B to its normal position, as hereinafter described. This spring 7a is, however, not strong enough 'to turn the wheel E until the latter iS released 95 from the detent.

To explain the operation of the apparatus, let it be supposed that it is required to communicate from No. 5 station (that shown in the drawings) with one of the distant sta- 10c tions-say, for example, No. 3. The attendant at No. 5 station first turns the movable contact B by means of the handle C into contact with the stationary contact a., corresponding to No. 3 on the scale, in which position the piece B is retained by the detent h, engaging the teeth of the notched wheel E. Then by depressing the button G, so as to make contact of the tongue wwith the bridge-piece z, a circuit will be completed through the line No. 3, Fig. 4, which will ring the bell at No. 3 station, if the apparatus at that station is disengaged. The attendant then removes the telephone-receiver J from the hook of the switch-lever K, which, under the action of a spring L, will be raised, so as to cause a'projection w thereon to make contact with springcontact pieces at m and n, whereby circuits are completed through thetelephone-transmitterl and receivers J of both stations, so that conversation between the attendants at the two stations may be maintained. Projecting from the ratchet-wheel E is an arm @,the outer end of which, when the contact B is in its normal position at 0, (zero,) bears against a bladespring u, carried by a slide t, which is raised and lowered with the switch-lever K. When the movable contact B is moved into contact with either of the stationary contacts a other than that marked 0, (zero,) the end of the arm v leaves the blade-sprin g u, which then springs forward, bringing its lower end against the outer end of the lever F, carrying the detent h. When the telephone is removed fromthe hook or lever K, the said hook is raised by the spring L, and with it the spring u, which is attached to the slide t, to which the hook is connected. The lower end of the spring u, being thus raised above the end of the lever F, sprin gs forward, so that when the telephone is replaced on the hook K the weight thereof carries the hook down and with it the spring u, and the lower end of the latter presses on the end of the lever F. When the attendant has finished using the receiver, he hooks it onto the lever K, which will then descend by the weight and break the circuit through the telephone receivers and transmitters and make contact at sin connection with the bell 'r (shown under the transmitter in Fig. l) in readiness to be called. At the saine time by the descent of the lever K the slide z5, carrying the blade-spring u, which now lies over the lever F, is also lowered, so that the end of the said spring u presses on the end of the lever F, and so disengages the detent h from the teeth of the wheel E. This wheel will then, under the action of the spiral spring k, be partially rotated, and thereby return the contactB to its normal position O, (zero.) The tail end of the lever o will then come again into contact with the blade-spring u and press back the said blade-spring u out of the range of the lever F, so that the detent h will then again engage with the teeth of the ratchetwheel E in readiness for the next opei'ation. I will now proceed to describe the circuits at the dierent stages of the operation, referring to the diagrams, Figs. 5, 6, '7, and 8.

Fig. 5 shows the contacts and the direction of the current when the apparatus Vis in its normal condition to receivea call. The telephone-receiver J being on the hook K, the circuit is completed as follows: An electric current from a distant station arrives at the terminal L of the line-wire and passes by the blade-spring ato the adjustable contact-piece B, thence by the wire c to the tongue and contact-piece h2 of the calling-key, and thence by the wire d to the switch-hook K, and through the projection w to the contactspring s, from whence it passes by the wire e to the coils of the magneto-bell 0, thereby sounding the bell. From the coils of the bell the current passes by the wire f and terminal g to earth or to a return-wire connection to earth.

Fig. 6 shows the connections and course of the current when answering a call. To answer a call, it is not necessary to remove the telephone from the hook K. All that is required is to depress the button G, so as to make contact of the tongue a: with the bridge-piece z, whereuponthe current from the battery q is conducted by the wire to terminals l', and from thence by the wire j to the coil 3 of the audible indicator or visible vibrator 6, and thence by the wire t" to the bridge z of the calling-key G, and by the Wire c to the adjustable contact B and therefrom by the bladespring a to line-Wire L', by which it is conducted to the bell of the instrument at the other end of this line, and thence to earth or by a return-wire and wire t to terminal g', and thence by wire V to battery q', and thus complete the circuit.

Fig. 7 shows the connections and course of the current when one station is calling another station, station No. 3 beingrepresented as calling up station No. 5. The adjustable contact-arm B of No. 3 station being adjusted to make contact with spring-contact ain connection with the line-wire leading to N o. 5 station, the button G of N o. 'instrument is depressed, so as to make contact of the tongue x thereof with the bridge z. A current from the batteryq in connection with No. 3 station there passes by the wire c2 to terminal e', thence by the wire j to coil 3 of audible or visible indicator 6, and from thence by the wire i to bridge-piece ,e and tongue a; of callkey G, and by wire c to the adjustable contact-arm B. The current travels thence by the blade-spring a in connection with linewire 5, and through the said line-wire to the instrument at No.5 station, entering the said instrument by the wire g, and passing to the contact-piece a marked O, (zero,) thence by the adjustable contact B and wire' c to the tongue and contact-piece h2 of the calling-4 key G of the No. 5 instrument, and is conducted therefrom to the switch-hook Kbythe wire d', and thence by the projection fw, contact-spring s, and wire e to the bell fr. From the bell fr the current travels through the wire f to terminal g', thence by the wire t to earth, or by return-wire to the instrument at No. 3 station, the current entering the instrument at this station by the wire t to terminal g', and passes thence by wire V to the battery q to complete the circuit.

Fig. S shows the connectionsand direction of the currents when the persons at two stations (3 and 5, for example) are conversing. Each person has now removed his telephone from the hook K, whereupon in each of the instruments the hook K is raised under the action of the spring L, and the battery-cells placed in circuit with thetransmitter, the circuit therethrough being completed as follows: From the battery q the current passes by the wire k to the terminals P, thence by the wire l to the primary wire of the induction-coil M, and therefrom by the wire 3X to the transmitter I. From the transmitter the current passes by the wire X and contact-springs 5X and 6X and wire 7X to terminal g,and thence by the wire V to battery q', the circuit be ing thus completed through the transmitter. The circuit through the line is as follows: Starting at station No. 3, the current from the switch-hook K of the instrument at the station passes by the wire d to contact-piece h2 and tongue al of the calling-key G, and thereupon by the wire c to the adjust-able contact arm B. From the arm B the current passes to blade-spring a in connection with linewire No. 5, through which it passes to the instrument at No. 5 station, the current entering the said instrument by the wire g, connected to spring-contact a, marked 0, (zero,) and passing to the adjustable arm B, thence by the wire c to the tongue and contact h2, and therefrom by the wire d', switch-hook K, projection w, contact-springm, and wire S to terminal 9 ot the telephone-cord l0 to the telephone-receiver J. From the receiver J the current passes through the cord 10 to the terminal 1l, and thence by the wire l2 to the secondary wire of the induction-coil M, and therefrom by the wire 13 to the terminal g', and thence by the wire t and earth or return wire to the instrument at No. 3 station, entering the said instrument by the wire t and passing to terminal g', thence by the wire 13 to the secondary wire of the inductional coil M of that instrument. The current then passes by the wire l2 to terminal ll of the cord l0 of telephone-receiver J, and thence by the cord 10 to terminal 9, wire 8, contactspring m, and projection w to switch-hook K to complete the circuit through the telephonereceiver.

In Fig. 3 is shown at 3 5 an audible indicator, and at 6 in Fig. l is shown a visible indicator for indicating whether or not a distant station be engaged; but Ido not restrict myself to the arrangements shown, as they may be considerably modified.

The audible indicator shown in Fig. 3 consists of a coil 3, placed in the circuit and attached by a bracket 4 to the back of the front board A of the switch. Opposite the coil 3 is pose of calling up a distant station and the;

instrument at that station is disengaged, the

bell-circuit at that station will be completed t `through the coil 3, and the armature 4: will be caused to vibrate against the core of the coil 3, which will be heard by the attendant, and thus indicate that the distant station is at liberty. strument at the distant station has `been moved from its position at Zero for the pur' pose ot' calling up some other station, the bellcircuit at that station will be cut out, and consequently no current will pass through the core 3 and the armature 4 will remain stationary and no sound be heard, thereby indicating that the distant station is engaged. It the movable contact B at the distant station be in its position at zero, but the receiver J has been removed from its hook, the current will be short-circuited through the coil 3 and cause the armature 4e t0 be attached against the core of the coil 3, giving thereby one sound only, thus indicating that the distant station is being spoken with. In like manner the pointer 6 of the visible indicator, Fig. l, is caused to vibrate with the armature l or to remain stationary, as the case may be, and thus visibly indicate the condition of the distant station.

I claim as my inventionl. In a switch for telephone-circuits, the combination of a number of stationary contacts, each in circuit, with a separate and distinct telephone apparatus, an adjustable contact-piece free from control of the support for the telephone-receiver, a notched wheel or segment and detent for retaining the adjustable contact-piece inits adjusted position, and

It the movable contact B of the in'- Y IOC means for releasing the said contact-piece and returning it to its normal position by placing the telephone-receiver on its support, substantially as described.

2. In a switch for telephone-circuits, a number of contact-pieces in circuit with separate and distinct telephone apparatus, and an adj ustable contact-piece capable of being moved into position to connect the calling-circuit with any one of the said separate apparatus without removing the home receiver from its support, in combination with a notched wheel or-segment, with a yielding detent to retain the adjustable contact-piece in its adjusted position, a device controlled by the movable support for the telephonie receiver and adaptedto come into line with the yielding detent when the-receiver is raised from its support and to free the detent when the receiver is replaced, and a spring to return the adjustable contact-piece to its normal position, all substantially as described.

3. In a switch for telephone-circuits, the combination of the stationary contact-pieces a in the circuits of separate and distinct telephone apparatus, adjustable contact-piece B, capable of being adjusted or moved into con- IIO tact with any one of the stationary contacts a and free from control of the support for the telephone-receiver, the notched Wheel or segment E, detent h, and spring k, for retaining the contact-piece B in its adjusted position and for returning the said contact-piece to its normal position When the detent is disengaged from the teeth on the wheel or segmentE, the Whole being arranged to operate substantially as described.

4. In a switch for telephone-circuits, a number of stationary contacts, each in circuit with a separate and distinct telephone appal ratus, in combination with an adjustable contact-piece capable of being moved intovany required position Without removing the telephone-receiver from its support, a notched wheel or segment, a detent for retaining the ALFRED GRAHAM.

XVitnesses:

W. M. MENzIEs, IVM. T. MARNS, Both of lVo. 109 Fwmingdon Road, London, 

